The present invention relates to an arm for locating a probe on a coordinate positioning machine, such as a machine tool or a coordinate measuring machine.
It is known to locate a probe on a machine tool, for example, by means of an arm which is either manually or automatically removable from the working area of the machine, and whose position (and thus the position of a probe supported on the arm) when situated within the working area of the machine is repeatable. In this way a probe supported on the arm may be positioned within the working area of the machine when required to perform an inspection or toolsetting operation, for example, and then be removed from the working area during machining. Typically, signal connections between the probe and the machine controller (including any interface on the machine which may be required to connect the probe to the controller) are made via the arm, for example by means of cables routed within the arm. Such signals are fed to the control of the machine tool via signal contacts which are operably connected at least when the arm is positioned to locate the probe within the working area of the machine, and which may be broken when the arm is removed from the working area.
According to a first aspect of the present invention, there is provided an arm for locating a probe on a coordinate positioning machine which has indicia provided thereon indicating the status of signals output from the probe.
In one preferred embodiment of the present invention, the indicia are provided by a plurality of light sources, having different colours, with each colour being indicative of a particular probe signal status. For example, one light source may indicate proper connection of the probe to the machine controller, and thus correspond to a status of xe2x80x9cprobe readyxe2x80x9d, while another may indicate (in the case of a trigger probe, for example) that probe trigger has occurred.
In a further preferred embodiment, the arm includes a signal conditioning circuit which supplies power to the probe, and receives signals from the probe, the signal conditioning circuit producing, on the basis of the probe signal, a plurality of output signal values, one output indicative of each possible probe status, wherein the signal conditioning outputs are connected to the machine controller and/or interface via the light sources, and each signal conditioning output is identifiable to the machine controller and/or interface from the value of one or more of the parameters of the signals passing through the light sources.
Thus, a change in the signal conditioning output may result in one of the light sources being switched off, and another switched on. By using different coloured LEDs which have different efficiencies and hence use different amounts of current, such a change would be manifested to the machine controller and/or the interface by monitoring, for example, the amount of current consumed by the operating light source.